Coupling FEM and CFD solvers for continuous casting process simulation using precice

The numerical investigation of continuous casting requires more than just one simulation technique. In continuous casting, liquid metal is continuously poured into a mould while the starting head is slowly moved downwards, which results in a growing metal ingot. Though, the ingot’s outer surface is solidified after the mould, its inside core is still a mixture of liquid and mushy phases. This mixture of physical states requires different numerical schemes to describe the constitutive behaviour and relation. While the liquid region is described in the Eulerian approach, the solid is well described in the Lagrangian approach. Commonly the finite volume method is chosen for the Eulerian and the finite element method for the Lagrangian perspective. Consequently, it is logical to combine a CFD solver with a FEM solver for an ideal numerical representation of the continuous casting process. The coupling of two different solvers communicating in two different programming languages - in the present work OpenFOAM and LS-DYNA - is not an easy task. However, preCICE enables the coupling of the different solvers with a minimum of intrusive functions. The present work deals with the first step towards the coupled simulation routine for the continuous casting process. A first basic simulation of a simple plate was setup consisting of OpenFOAM for the Eulerian approach and LS-DYNA for the Lagrangian approach. OpenFOAM calculates the temperature field due to time-dependent boundary conditions, while the mechanical LS-DYNA solver calculates resulting strains and stresses considering thermal strain. The aim of this simulation was to develop and test the preCICE adapter for LS-DYNA, as the adapter for OpenFOAM is already available and ready to use. The mapping techniques of preCICE did manage to achieve good energy conservation results. The first results showed a good correlation especially in the middle of the domain. The difference at the plates’ ends between the two different methods defined the next steps for the coupling

Revisiting Glauconite Geochronology: Lessons Learned from In Situ Radiometric Dating of a Glauconite-Rich Cretaceous Shelfal Sequence

The scarcity of well-preserved and directly dateable sedimentary sequences is a major impediment to inferring the Earth’s paleo-environmental evolution. The authigenic mineral glauconite can potentially provide absolute stratigraphic ages for sedimentary sequences and constraints on paleo-depositional conditions. This requires improved approaches for measuring and interpreting glauconite formation ages. Here, glauconite from a Cretaceous shelfal sequence (Langenstein, northern Germany) was characterized using petrographical, geochemical (EMP), andmineralogical (XRD) screening methods before in situ Rb-Sr dating via LA-ICP-MS/MS. The obtained glauconite ages (~101 to 97 Ma) partly overlap with the depositional age of the Langenstein sequence (±3 Ma), but without the expected stratigraphic age progression, which we attribute to detrital and diagenetic illitic phase impurities inside the glauconites. Using a novel age deconvolution approach, which combines the new Rb-Sr dataset with published K-Ar ages, we recalculate the glauconite bulk ages to obtain stratigraphically significant ‘pure’ glauconite ages (~100 to 96 Ma). Thus, our results show that pristine ages can be preserved in mineralogically complex glauconite grains even under burial diagenetic conditions (T < 65 ◦C; <1500 m depth), confirming that glauconite could be a suitable archive for paleo-environmental reconstructions and direct sediment dating.Esther Scheiblhofer, Ulrike Moser, Stefan Löhr, Markus Wilmsen, Juraj Farkaš, Daniela Gallhofer, Alice Matsdotter Bäckström, Thomas Zack, and Andre Balderman

Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers

A primary concern in a multitude of industrial processes is the precise monitoring of gaseous substances to ensure proper operating conditions. However, many traditional technologies are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative but suffer from high cost and limited accuracy in highly cluttered industrial plants. This paper examines the performance limits of low-cost frequency-modulated continuous-wave (FMCW) radar sensors for permittivity measurements. First, the accuracy limits are investigated theoretically and the Cramér-Rao lower bounds for time-of-flight based permittivity and concentration measurements are derived. In addition, Monte-Carlo simulations are carried out to validate the analytical solutions. The capabilities of the measurement concept are then demonstrated with different binary gas mixtures of Helium and Carbon Dioxide in air. A low-cost time-of-flight sensor based on two synchronized fully-integrated millimeter-wave (MMW) radar transceivers is developed and evaluated. A method to compensate systematic deviations caused by the measurement setup is proposed and implemented. The theoretical discussion underlines the necessity of exploiting the information contained in the signal phase to achieve the desired accuracy. Results of various permittivity and gas concentration measurements are in good accordance to reference sensors and measurements with a commercial vector network analyzer (VNA). In conclusion, the proposed radar-based low-cost sensor solution shows promising performance for the intended use in demanding industrial applications

Phase Estimation Mean Square Error and Threshold Effects for Windowed and Amplitude Modulated Sinusoidal Signals

Publication in the conference proceedings of EUSIPCO, Florence, Italy, 200

Coupling FEM and CFD solvers for continuous casting process simulation using precice

The numerical investigation of continuous casting requires more than just one simulation technique. In continuous casting, liquid metal is continuously poured into a mould while the starting head is slowly moved downwards, which results in a growing metal ingot. Though, the ingot’s outer surface is solidified after the mould, its inside core is still a mixture of liquid and mushy phases. This mixture of physical states requires different numerical schemes to describe the constitutive behaviour and relation. While the liquid region is described in the Eulerian approach, the solid is well described in the Lagrangian approach. Commonly the finite volume method is chosen for the Eulerian and the finite element method for the Lagrangian perspective. Consequently, it is logical to combine a CFD solver with a FEM solver for an ideal numerical representation of the continuous casting process. The coupling of two different solvers communicating in two different programming languages - in the present work OpenFOAM and LS-DYNA - is not an easy task. However, preCICE enables the coupling of the different solvers with a minimum of intrusive functions. The present work deals with the first step towards the coupled simulation routine for the continuous casting process. A first basic simulation of a simple plate was setup consisting of OpenFOAM for the Eulerian approach and LS-DYNA for the Lagrangian approach. OpenFOAM calculates the temperature field due to time-dependent boundary conditions, while the mechanical LS-DYNA solver calculates resulting strains and stresses considering thermal strain. The aim of this simulation was to develop and test the preCICE adapter for LS-DYNA, as the adapter for OpenFOAM is already available and ready to use. The mapping techniques of preCICE did manage to achieve good energy conservation results. The first results showed a good correlation especially in the middle of the domain. The difference at the plates’ ends between the two different methods defined the next steps for the coupling

Radio-Acoustic-Sounding System berührungslose und abstandsaufgelöste akustische Temperaturmessung im industriellen Umfeld

Dieser Artikel beschreibt einen Messaufbau für die berührungslose, abstandsaufgelöste Temperaturmessung von Gasen. Die elektromagnetisch-akustische Wechselwirkung, bekannt von der Radio-Acoustic-Sounding Methode, macht es möglich, auch im industriellen Umfeld kontinuierlich Temperaturen zu messen. Dazu wird die Schallgeschwindigkeit, welche in einem eindeutigen Zusammenhang mit der Temperatur steht, mit einem Doppler-Radar bestimmt. Das Funktionsprinzip, ein realisierter Aufbau und dessen Herausforderungen werden aufgezeigt und mit Messungen dargestellt. Weiteres wird diskutiert, wie mit diesem Messprinzip neben der Temperatur auch Luftströmungen mehrdimensional bestimmt werden können.This article describes a measurement setup for non-contact, spatially resolved temperature measurement of gases. The electromagnetic-acoustic interaction, known from the radio-acoustic-sounding method, makes it possible to measure temperatures continuously in the industrial environment. For this purpose, the speed of sound of an emitted sound pulse, which is temperature-dependent, will be determined with a Doppler radar. The operating principle, a possible setup and its challenges are shown and presented with measurements. Further, it is discussed how air flows or temperatures can be determined multidimensionally with this measuring principle.(VLID)336543

Accuracy Bounds and Measurements of a Contactless Permittivity Sensor for Gases Using Synchronized Low-Cost mm-Wave Frequency Modulated Continuous Wave Radar Transceivers

A primary concern in a multitude of industrial processes is the precise monitoring of gaseous substances to ensure proper operating conditions. However, many traditional technologies are not suitable for operation under harsh environmental conditions. Radar-based time-of-flight permittivity measurements have been proposed as alternative but suffer from high cost and limited accuracy in highly cluttered industrial plants. This paper examines the performance limits of low-cost frequency-modulated continuous-wave (FMCW) radar sensors for permittivity measurements. First, the accuracy limits are investigated theoretically and the Cram&eacute;r-Rao lower bounds for time-of-flight based permittivity and concentration measurements are derived. In addition, Monte-Carlo simulations are carried out to validate the analytical solutions. The capabilities of the measurement concept are then demonstrated with different binary gas mixtures of Helium and Carbon Dioxide in air. A low-cost time-of-flight sensor based on two synchronized fully-integrated millimeter-wave (MMW) radar transceivers is developed and evaluated. A method to compensate systematic deviations caused by the measurement setup is proposed and implemented. The theoretical discussion underlines the necessity of exploiting the information contained in the signal phase to achieve the desired accuracy. Results of various permittivity and gas concentration measurements are in good accordance to reference sensors and measurements with a commercial vector network analyzer (VNA). In conclusion, the proposed radar-based low-cost sensor solution shows promising performance for the intended use in demanding industrial applications